Post script -- I replaced all the power tubes in my VS-115 with KT-120s. Aside from my sense that these tubes greatly improved the sound quality of my VS-115 as compared to the old 6550Cs, I understand that the KT-120s have a more robust build quality. So far, evrything is humming (pun - LOL). Again, FWIW.
Perhaps Gary (Hifigeek) can weigh in on his KT-120 experience. Gary is an ARC authorized service tech.
Perhaps Gary (Hifigeek) can weigh in on his KT-120 experience. Gary is an ARC authorized service tech.